PROTECTION ARRANGEMENT OF A DEFLECTION CIRCUIT

摘要

A deflection switch of a horizontal deflection circuit is coupled to a retrace resonant circuit that includes a horizontal deflection winding and a first retrace capacitance. A flyback transformer primary winding is coupled to a junction terminal of the deflection switch and the retrace resonant circuit. An East-West modulation current is generated by a bidirectional second switch having a conduction time that is phase modulated during horizontal retrace at a vertical rate in a parabolic manner. The second switch is coupled in series with the deflection switch during the entire trace interval. To prevent an over-current condition when the current in the second switch exceeds a predetrermined first level, the second switch is turned off and interrupts the flow of current through the deflection switch. Additionally, a diode is coupled between an intermediate terminal of the transformer primary winding and a junction terminal of the deflection and the second switches for preventing an overvoltage condition from developing across the second switch.